The Battle of the Frontiers was the gigantic clash that would make or break the hopes of both Germany and France. The two great competing visions of the war – the latest versions of the Schlieffen Plan and the French Plan XVII – were put to the ultimate test, moving at long last from theory to practice. The battles were fought along the Eastern French border and in South Belgium. In the end the Franco-British forces were driven back, allowing the German forces to invade Northern France.
The German Army was a professional body that took war very seriously. The German main thrust, which would ultimately set the agenda, was the advance of the First and Second Armies across the Belgian border and deep into northern France. The neighboring Third Army would also pass through the Belgian Ardennes. The Fourth and Fifth Armies would advance through Luxembourg and the French Ardennes. This meant that effectively all five armies would be performing a gargantuan wheeling manoeuvre to overwhelm the French left flank. Meanwhile, the German Sixth and Seventh Armies would stand fast in Alsace-Lorraine.
The French Army was also an extremely powerful continental army. But the vast size of the French Army concealed some fundamental weaknesses. Although great strides had been made to modernize the army, they had been hampered by the poisonous military politics of the day, which had affected its preparations for modern war. The French had yet to issue camouflage uniforms to their soldiers. The basic rifle issued to the French infantry was not equal to the demands of modern warfare. The French also lacked modern artillery weapons. There was a final defect in the French Army: a lack of proper tactical training.
Belgium had adopted the principle of compulsory military service only in 1912, following a strategic review, and it had taken little effect by 1914. Its army was one of the most old-fashioned in Europe.
The necessity of quickly capturing the fortresses at Liège in Belgium had much exercised the minds of German military planners in the years running up to the war. Liège lay within twenty miles of the German frontier and was defended by a series of twelve forts on either side of the Meuse River, which bisected the city. Thus it was the Belgian Army that would be the first to face the German onslaught. The Belgians hoped they would be able to hold the Liège fortress until Franco-British reinforcements arrived. The city fell first, ahead of the bulk of Belgian fortifications.
The Germans were at this point in the strange position of having taken the city itself, but not the bulk of the surrounding fortifications. The huge German mortar shells battered the forts one by one into submission. When the Fort de Pontisse, which commanded the crossings over the Meuse to the north of Liège, fell, the gateway to Belgium swung ajar for the German First Army to begin its advance. General Leman was trapped inside Fort de Loncin when the Germans commenced a dreadful bombardment.
The non-appearance of French and British forces persuaded the Belgian Field Army to withdraw towards Antwerp. Two days later the Germans entered Brussels.
To maintain their schedule and avoid leaving substantial rearguards, the Germans implemented a policy of Schrecklichkeit — frightfulness —by attempting to subdue the population by executing some civilians or destroying property. Memories of ‘free firing’ by irregulars against the Prussian advance into France in 1870 were strong and had been reinforced by official stricture. There were, later enquiries would reveal, civilians who resisted the German invasion in Belgium in 1914.
At Liège, as one might expect in a situation where troops without combat experience deploy new and untried weapons, the Germans wasted time and made mistakes. Just how quickly they learned can be seen from what happened at Namur, a place defended by nine forts and some thirty-six thousand men. The Germans deployed heavy weapons to pound the forts into submission. The Belgians had also learned. The infantry stayed on and fought, so Namur was partly a siege and partly a series of engagements. Even so, Namur lasted only five days.
The French had launched a major offensive up into Belgium. The Third and Fourth Armies attacked directly at the pivot of the German advance, going for the German Fourth and Fifth Armies, which were still largely inside Belgium. Already, words like ‘decimated’ and ‘annihilated’ were beginning to take on their literal meaning. In their first day of combat, entire elite French troops simply ceased to exist. France’s elite troops were being destroyed in small pockets all over the battlefield. The destruction of the French colonial troops was simply an extreme example of the disaster that overtook French arms, all in the space of one week in August 1914.
The French mobilization had concentrated all five of their field armies in northeast France. French troops had crossed the German border in an effort to secure an early morale-enhancing victory in Alsace. At first the French encountered a weak German resistance, but the German army was preparing its counterattack. The French suffered defeat ahead of their main attack.
Although irritated at this failure, Joffre still believed that the Germans had not committed their reserve divisions to the frontier battles. He was therefore confident that he would be facing just six, instead of the actual eight, corps in the Alsace-Lorraine area when he launched his main attack. He timed his attack to coincide with the expected Russian offensive on East Prussia. Once he was clear as to the line of the German assault in Belgium, he planned an attack north of Metz-Thionville striking at the weak hinge of the main German attack. The Germans were willing to cede ground as the French advanced across the border into Lorraine.
The French armies advanced up to eighteen miles in the first three days of the offensive: Mulhouse fell to Pau, Dubail captured Sarrebourg and de Castelnau’s men closed in on Morhange. Throughout, the Germans fought an excellent delaying battle, falling back, trying to avoid committing too many infantry units, while using artillery to inflict heavy casualties. A crushing counterattack was launched against the overstretched French Second Army in the Battle of Morhange. The French were forced to withdraw to their starting points on all fronts.
The main French reconnaissance force had repeatedly crossed the Ardennes without detecting the enemy's presence. As a result, the French High Command assured the regional commanders that ‘no serious opposition need be anticipated’. Reports from French aviators had confirmed this wholly false judgement. The Germans were better informed than the French. Their aviators had reported significant enemy movements on the front.
Joffre planned a second great offensive by his Third, Fourth and Fifth Armies striking through the lower Ardennes north of Metz-Thionville. Joffre’s mind was still firmly centered on the Ardennes offensive, intended to break through the German center and threaten the flank of the German Second Army wheeling through Belgium. The series of encounter battles that ensued on the 22nd of August were bloody affairs, complicated by the wooded hilly terrain and poor visibility caused by fog. When the French advanced they often found the Germans dug in on the forward edge of thick woods. At the end of that terrible day, the French fell back.
On the next day of the Ardennes offensive, Joffre wanted to renew the offensive but was soon thwarted. It was simply impossible to reorganize the shattered units; more pertinently, the Germans were driving deep into the French troops, throwing the Third and Fourth Armies right back to their start lines. There was widespread chaos; no one knew what was happening and terrible mistakes were made which added to the massive casualty toll. Yet it was not all one-way traffic. This was open warfare and the Germans, too, could be caught unawares. When they had the chance, the French 75 mm guns could provide formidable opposition.
The Battle of the Frontiers had not gone well for France. The Germans advanced through Belgium, capturing Brussels and sweeping aside the Belgian Army, which fell back on Antwerp. Joffre had still not grasped the scale of the German threat and issued orders for an attack across the Sambre. This offensive intent would be forestalled when von Bülow launched his own offensive, crossing the Sambre between Namur and Charleroi. Over the next two days of severe fighting known as the Battle of Charleroi, the Fifth Army was attacked on both flanks and forced back, first from the Sambre, then from the Meuse.
Despite the tactical defeats which they had borne, the French armies were intact. True, some units in the Battle of the Frontiers suffered horrific casualties. Total French losses reached 260,000, including 75,000 dead. But the impact varied considerably according to regiment, division, and even army. France was able to make up its losses. In the same period, fifty-four of eighty-six German divisions were in action, including seventeen reserve divisions to only four French. The Germans suffered 260,000 casualties while the British had 30,000.
From Alsace, through Lorraine and the Ardennes to Charleroi, the Allied armies had been forced to retreat. Joffre reported to General Alphonse Messimy that his armies would be passing from the offensive to the defensive: 'Our object must be to last out as long as possible, trying to wear the enemy out, and to resume the offensive when the time comes.' The French had greatly underestimated the Germans both in terms of tactics and strength. The opening defeats were the sanction which Joffre needed in order to reconstitute the French army.